4. Calculational Definitions and Desired Results

 
4.1 Beginning-of-Life Calculations

 Table 3 contains the list of calculations that are to be performed at BOL with fresh fuel material. The calculations are to be performed both for the assembly configuration with only water in the guide tubes and with burnable poison rods in the guide tubes.

 
The desired results for the BOL calculations are:

1. Ratio of total neutron production to total absorption
2. Effective multiplication factor (k_eff)
3. Pin fission density distribution (normalized)
4. Total Capture and fission rates and fraction of the total capture and fission rates by
     ²³⁵U, ²³⁸U, ²³⁹Pu, ²⁴⁰Pu, ²⁴¹Pu, ¹³⁵Xe in each pin.
5. The ¹³⁵Xe concentration in each pin for the HFP cases only.

 The pin fission density density should be normalized such that the average value is unity.

4.2 Burnup Calculations

A three-cycle irradiation of the assembly is to be performed in the HFP conditions using a constant soluble boron concentration of 550 ppm. Each cycle burnup is 15 GWD/MTHM and results in a discharge burnup of 45 GWD/MTHM. The burnable poison rods are present in the first cycle and are removed for the subsequent two

cycles (the guide tubes remain). The following results are desired at each 1.5 GWD/MTHM increment (30 intervals over the three-cycle irradiation):
 

1. Ratio of total neutron production to total absorption
2. Effective multiplication factor (k_eff)
3. Total capture and fission rates and fraction of the total capture and fission rates by
     ²³⁵U, ²³⁸U, ²³⁹Pu, ²⁴⁰Pu, ²⁴¹Pu, ¹³⁵Xe, and total fission products for the entire assembly
4. U, Np, Pu, Am, and Cm content and isotopics for the entire assembly

In addition, at each 7.5 GWD/MTHM increment (middle and end of cycle) the following quantities are desired (6 intervals over the three-cycle irradiation):

5. Pin fission density distribution
6. Total capture and fission rates and fraction of the total capture and fission rates by
     ²³⁵U, ²³⁸U, ²³⁹Pu, ²⁴⁰Pu, ²⁴¹Pu, ¹³⁵Xe and total fission products in each pin
7. U, Np, Pu, Am, and Cm content and isotopics in each pin
 

4.3 End-of-Life (EOL) Calculations
 

Using the EOL conditions from Section 4.2 perform the calculations given in Table 4. For the EOL cases, the ratio of production to absorption and the effective multiplication factor (k_eff) are to be calculated.

4.4 Other Calculational Results and Data

A complete description of the data libraries and codes used to perform the calculations should be submitted. This description should include the origin of the cross section data, methods used for the cross section processing, and methods used for the k_eff and power distribution calculations. In the case of discrepancy, participants should be prepared to submit cross sections and neutron fluxes in a energy group structure to be determined later along with detailed fission product inventories.

 
4.5 Submission of Electronic Results

For comparison purposes it is desirable that all results be submitted electronically for distribution. For simplicity it is recommended that all pin-by-pin results be arranged in tabular format by pin number as shown in Figure 1. An example of such a table is given in Appendix B. The results for each benchmark section should be grouped together and well labeled.